Matrix holder for dental attendance



Nov. 7, 1950 J. MULLER MATRIX HOLDER FOR DENTAL ATTENDANCE Filed Feb. 21, 1947 Patented Nov. 7, 1950 MATRIX HOLDER FOR DENTAL ATTENDANCE Josef Miiller, Fribourg, Switzerland Application February 21, 1947, Serial No. 730,146 In Switzerland August 5, 1942 Section 1, Public Law 690, August 8, 1946 Patent expires August 5, 1962 Claims.

This invention relates to matrix holders for dental attendance. Matrix holders used up to date for holding matrix bands for surrounding a tooth to be treated show the disadvantage that they do not allow an adaptation of the band to the conicity of the tooth. They all hold the bands in such a way that the latter fit perfectly at the crown end of the tooth, but badly below this part. Owing to the fact that the guide means of these known holders do not allow the band to fit to the bottom part of a tooth while the band under the effect of the tightening force has a tendenc to do so, a load occurs leading to a quick failure of the band. Besides this, known holders are only available in certain standardized sizes, or the matrix bands are of a special shape to be used only in holders of a certain type. There is, for instance, a holder having small holding heads engaging special recesses of the matrix bands, these recesses, of course, being made on the manufacture of the bands. There are holders in which the bands, after having left their guide, are sharply bent into tightening direction. This abrupt change in direction results in frequent failures. There was hitherto but one single holder for celluloid matrices, forming a scissorlike clamp causing an unequal load in the celluloid band, resulting in a tearing of the same.

The matrix holder according to the invention having a supporting plate for the tooth, provided with slots for guiding the matrix band, remedies the above inconveniences and may be used for matrix bands of any material and any size and shape. It is characterised in that the slots are arranged slantwise with regard to one another for the purpose of adapting the matrix to the conicity of the tooth to be treated.

The accompanying drawings illustrate, by way of examples, two embodiments of the object of invention.

Fig. 1 is a horizontal section, on a considerably enlarged scale, of the matrix holder according to the first example, abutting against a tooth,

Fig. 2 is a top view upon the supporting plate, likewise on a considerably enlarged scale,

Fig. 3 is a section similar to Fig. 1 but of the second embodiment,

Fig. 4 is a section along the line IV-IV in Fig. 3 and Fig. 5 is a top view upon the supporting plate of the second example, on a considerably enlarged scale.

Referring to Figs. 1 and 2, the matrix band I (for instance made of steel or celluloid) is placed around the tooth but is not already tightened. A bolt 3 is screwed through a middle member 4 and these surfaces by tightening the screws I6.

2 carries on its one end a hand button 5 and on its other end a supporting plate 6 abutting against the tooth 2. This supporting plate ii is fixed in a loose manner b means of the screw I to the bolt 3 so that the bolt 3 may even be turned when the plate t is applied to the tooth. As may be seen from Fig. 2, the supporting plate 6 has two slanting slots 8 provided for the purpose of guiding the matrix band and of adapting the band to an ordinary conical shaped tooth, so that a perfect joint may be obtained from the crown down to the bottom part of the tooth. The middle member 4 has two slots 9 through which the ends of the matrix band are drawn and wherein they are clamped fast in that they are pressed against the middle member by means of small discs II fixed to screws IE! screwed into the middle member 4. As may be seen in Fig. 1, the matrix band I, on turning the button 5, is tightened and fitted to the tooth, while the band, after the slots 8, is not sharply bent butruns substantially in the same direction along which it traverses the slots and is also tightened substantially in this direction. Thereby, fractures of the band are avoided.

The supporting plate 8 may be easily replaced by one of another size or with another inclination of the slanting slots.

Referring now to Figs. 3 to 5, here too, the' supporting plate 6 is loosely fixed to the bolt 3, so that the latter ma be turned even when the plate contacts the tooth. As may be seen in Fig. 5 the plate 6 has two slanting slots 8 for guiding the matrix band I (e. g. made of steel or celluloid) when placed around the tooth as shown in Fig. 3. As in the first example the inclination of the slots 8 is adapted to the conicity of the tooth in order to obtain a perfect joint around the tooth. The bolt 3 is screwed through a middle member 4 and carries the button 5 by whose rotation the bond I clamped fast by the device described below is tightened and fitted to the tooth.

With reference to Fig. 4, the middle member 4 has two slanting flat surfaces I2 whose mutual inclination is substantially that of the slots 8 of the plate 6. Levers M are articulated on the middle member 4 by means of pins E3, the surfaces I5 of these levers turned towards the surfaces 22 being likewise fiat. Screws I5 adjustably screwed into the middle member 4 go through the ends of the levers M turned away from the pins It. The ends of the matrix band I are drawn through the space between the surfaces I2 and Iii and are clamped fast between As shown in Fig. 4, the ends of the band are clamped fast over their whole width so that even very thin bands are firmly gripped. The matrix band may even be of a very small width and fitted to any place whatever of the tooth (nearer the crown or nearer the bottom part), it will always be securely clamped fast by the levers it and the surfaces l2. Therefrom it follows that the same matrix holder may be used for several bands of different width.

Owing to the fact that the mutual inclination of the surfaces l2 and E5 is substantially the same as that of the slots t of the plate 6, any torsion of the band l between the plate 8 and the clamping device is avoided.

What I claim is:

1. In a matrix holder for dental attendance, the combination of a middle member; a screw adjustably engaging the middle member; a supporting plate mounted on said screw and having a supporting surface for engaging against a tooth to be treated, said supporting plate also having a pair of slanting slots closed at both ends and spaced apart with the distance be tween hem decrcasiir from one end portion of said sup orting surface toward the opposite end portion thereof, in order to adapt a matrix band to the conicity oi the tooth to be treated when said matrix band is drawn through said slanting slots; clamping levers rotatably mounted on said middle member to revolve about axes substantially parallel to the axis of said screw; and tightening means engaging said clamping levers and said middle member in order to clamp fast the portions of the matrix band extending between said middle member and said clamping levers and extending with its entire width betwee tightening means and the axes upon w h clamping levers revolve.

2. 'In a matrix side" for dental attendance, the combinat on 0 a supporting plate having a supporting surf ce for engagement against the tooth to be treated, having a pair of slanting slots spaced apart with the distance between them decreasing from one end portion of said supporting surface toward the opposite end portion thereof, in order to adapt a matrix band to the conicity of the tooth to be treated when said matrix band is drawn through said slanting slots; at middle member having slanting sur faces with a mutual inclination substantially the same as that of said slanting slots; a screw adjustably engaging said middle member and carrying said supporting plate; clamping levers rotatably mounted on said middle member to revolve on axes substantially parallel to the axis of said screw disposed in front of the slanting surfaces on said middle member in order to retain said matrix band between levers and said slant g surfaces of said middle member; and tightening means engaging said clamping members and said middle member to clamp fast the portions of the matrix band extending between said slanting surfaces of said middle member and said clamping levers with the longitudinal edges thereof extending transversely with respect to the longitudinal edges of said clamping levers.

3. In a matrix holder for dental attendance, the combination of a supporting plate having a supporting surface for engagement against the tooth to be treated, and having a pair of slanting slots spaced apart with the distance between them decreasing from one end portion of saidsupporting surface toward the opposite end portion thereof, in order to adapt a matrix band to the conicity of the tooth to be treated when said matrix is drawn through said slanting slots; a middle member having slanting surfaces with a mutual inclination substantially the same as that of said slanting slots; a screw adjustably engaging said middle member with its axis substantially parallel to the slanting surfaces on said middle member and carrying said supporting plate in a position disposing the supporting surface thereof substantially perpendicular to the aXls of said screw; clamping levers rotatably mounted on said middle member to revolve on axes substantially parallel to the axis of said screw and disposed in front of the slanting surfaces on said middle member in order to retain said matrix band between said levers and said slanting surfaces of said middle member; and tightening means engaging said clamping members and said middle member to clamp fast the portions of the matrix band extending between said slanting surfaces of said middle member and said clamping levers with the longitudinal edges thereof extending transversely with respect to the longitudinal edges of said clamping levers.

4.. In a matrix holder for dental attendance, the combination of a unitary supporting plate having a supporting surface for engagement against the tooth to be treated, and having a pair of independent closed narrow slanting slots spaced apart from each other at an invariable distance with said distance between said independent closed narrow slanting slots decreasing from one end portion of said supporting surface toward the opposite end portion thereof, in order to forcibly bend into slanting position the holding portions of a matrix band drawn through said independent closed narrow slanting slots and thereby adapt said matrix band to the conicity of the tooth to be treated.

5. In a matrix holder for dental attendance, the combination of a middle member; a screw adjustably engaging the middle member; a unitary supporting plate mounted on said screw and having a supporting surface for engaging against a tooth to be treated, said supporting plate also having a pair of independent closed narrow slanting slots spaced apart from each other at an invariable distance with said distance between said independent closed narrow slots decreasing from one end portion of said supporting surface toward the opposite end portion thereof, in order to forcibly bend into slanting position the holding portions of a matrix band drawn through said independent closed narrow slanting slots and thereby adapt said matrix band to the conicity of the tooth to be treated; clamping members rotatably mounted on said middle member to revolve about axes extending transversely of said supporting plate; and tightening means engaging said clamping members and said middle member in order to press said clamping members against said middle member.

JOSEF MULLER.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Number Name Date 814,056 Leffingwell Mar. 6, 1996 912,810 Carleton Feb. 1-6, 1909 

